Create a nagios config for dirauths

Description

We should create a nagios config that provides core tor developers with notification, logs, and vote and descriptor data in the event of a failure of one or more directory authorities.

If Nick and Sebastian had not been able to get descriptor and log lines from Jake and Linus, the fix for the IPv6 catastrophe would have taken even longer, possibly long enough for the network to completely fail.

A simple version of this would be to modify Tor Weather just to provide immediate notification for dir auth operators. But in an ideal world, if some threshold of dir auths failed, logs and descriptor data would get sent to an email alias.